Picture-framing clamp

ABSTRACT

A novel clamp is disclosed for holding the sides of a picture frame or the like inserted therein in abutting relationship for assembly. The clamp, in a preferred embodiment thereof, comprises four right-angled corner blocks encircled by a flexible cord, the ends of which are wound upon a rotatable spool rigidly attached to one of the corner blocks so as to draw the corner blocks together and thus maintain the sides of the inserted frame mutually aligned and under compression. A locking pin cooperates with registry holes or recesses on the rotatable spool to prevent the spool from unwinding inadvertently while the cord is under tension. The clamp further includes a pair of rods, each rod being secured to one of the corner blocks and slidably passing through an adjacent corner block to thus form two pairs of slidably interconnected blocks. In this fashion, the two slidably interconnected blocks of each pair are maintained in essentially constant orientation relative to each other, thus maintaining the clamp as a whole and the frame inserted therein in a rigid and stable configuration while under compression.

United States Patent Clifford H. Day

P.O. Box 602, McLean, Tex. 79057 [21] Appl. No. 846,041

[22] Filed July 30, 1969 [45] Patented Oct. 5, 1971 [72] inventor [54]PICTURE-FRAMING CLAMP 6 Claims, 7 Drawing Figs.

52 U.S.Cl 269/109,

269/130 51 mac: B25b5/02 so FieldoiSearch 269/108,

Primary ExaminerAndrew R. .luhasi Assistant Examiner-Z, R. BilinskyAttarney.lacobi, Lilling and Siegel ABSTRACT: A novel clamp is disclosedfor holding the sides of a picture frame or the like inserted therein inabutting relationship for assembly. The clamp, in a preferred embodimentthereof, comprises four right-angled corner blocks encircled by aflexible cord, the ends of which are wound upon a rotatable spoolrigidly attached to one of the corner blocks so as to draw the cornerblocks together and thus maintain the sides of the inserted framemutually aligned and under compression. A locking pin cooperates withregistry holes or recesses on the rotatable spool to prevent the spoolfrom unwinding inadvertently while the cord is under tension.

The clamp further includes a pair of rods, each rod being secured to oneof the corner blocks and slidably passing through an adjacent comerblock to thus form two pairs of slidably interconnected blocks. In thisfashion, the two slidably interconnected blocks of each pair aremaintained in essentially constant orientation relative to each other,thus PATENTEBUEI sign 3,510 512 1N VEN TOR. CLIFFORD H DAY ATTORNEYSPICTURE-FRAMING CLAMP BACKGROUND OF THE INVENTION This invention relatesto a device for clamping together work pieces for assembly, andspecifically concerns a clamp for holding the four sides of a pictureframe together in abutting, aligned relation while such sides are glued,nailed or otherwise secured together.

Picture frames or the like conventionally comprise four sides, each ofwhich is mitred at its ends at a 45 angle, so that when two adjacentsides are abutted, a right angle will be formed and the overall framewill be rectangular. The assembly of such a frame by hand, andparticularly holding of the sides together in an aligned condition,while nailing or cementing, is extremely arduous and oftentimes cannotbe successfully achieved.

For this reason, jigs or clamps are known in the art for maintaining thefour sides of the frame together in proper abutting relationship. Suchprior art clamps typically are bulky and comprise two pairs of clamps,acting either between opposite sides of the frame or across the twodiagonals of the frame, wherein each clamp of the pair must be set andtightened or loosened individually, which procedure is quitetime-consuming. Further such known clamps are generally limited to smallrange of adjustment and can therefore only be used for a specific sizeof frame or a limited frame size range.

A further known framing clamp is operable to simultane' ously clamp allfour sides of a frame by means of a worm gear arrangement. However,clamps of this type are generally quite heavy and require a substantialsupporting structure such as a machine table, and hence, are generallyimpracticable for smaller frames, particularly when produced on anindividual or limited basis.

SUMMARY OF THE INVENTION Thus, a need exists for a clamp assembly forpicture frames and the like which effectively eliminate theaforementioned drawbacks of the prior art constructions. It is theprimary object of the instant invention to satisfy this need.

Specifically, it is an object of the invention to provide a clamp forassembling a rectangular picture frame or the like, which clamp caneasily and quickly secure all four sides of a picture frame together bya single operation.

It is a further object of the invention to provide such a clamp which issimple in construction and has few moving parts.

It is still a further object of the invention to provide such a clampwhich is capable of operating over a wide range of adjustment andcapable of clamping very large or very small frames with equal facility.

These, as well as other objects and advantages which will becomeapparent as the description proceeds, are imple-,

mented by the invention which comprises a novel clamp for holding thesides of a picture frame or the like inserted therein in abuttingrelationship for assembly. The clamp, in a preferred embodiment thereof,comprises four right-angled comer blocks encircled by a flexible cord,the ends of which are wound upon a rotatable spool rigidly attached toone of the comer blocks so as to draw the corner blocks together andthus maintain the sides of the inserted frame mutually aligned and undercompression. A locking pin cooperates with registry holes or recesses onthe rotatable spool to prevent the spool from unwinding inadvertentlywhile the cord is under tension.

The clamp further includes a pair of rods, each rod being secured to oneof the comer blocks and slidably passing through an adjacent cornerblock to thus form two pairs of slidably interconnected blocks. In thisfashion, the two slidably interconnected blocks of each pair aremaintained in essentially constant orientation relative to each other,thus maintaining the clamp as a whole and the frame inserted therein ina rigid and stable configuration while under compression.

BRIEF DESCRIPTION OF THE DRAWINGS housing showing details of the spool;

FIG. 6 is a top plan view of the clamp in its closed or tightenedposition showing spacer members inserted for clamping a small pictureframe; and,

FIG. 7 is an enlarged perspective view of a single comer block with aspacer member inserted therein.

DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawings, andparticularly to FIG. 1 thereof, the inventive clamp will be seen tocomprise four generally cubical cooperating comer blocks designated 10,12, 14 and 16, respectively, constructed of wood or other suitablematerial. Each of these blocks is recessed at its upper inner comer asshown so as to define a square cornered depressed portion havingvertical sidewalls l8 and a horizontal surface 20, all mutuallyperpendicular to each other. In this manner, the four comer blockstogether define four comers of a rectangle which may be altered in sizeas will be more fully described hereinbelow.

An elongated guide rod 22 is rigidly embedded within and secured to eachof the comer blocks 10 and 12, and is generally centered thereinhorizontally and extends outwardly in the direction of blocks 14 and 16,as best seen in FIGS. 1 and 3. While the vertical positioning of each ofthese rod 22 is not critical, best results are obtained by locating theaxis of each rod 22 approximately midway between the horizontal surface20 and the bottom of the respective block. Comer blocks 14 and 16 eachhave an elongated hole drilled therethrough to slidingly receive one ofthe rods 22, and the respective blocks are then slid onto the rods asshown in FIG. I. It will be seen that in this manner two pairs of blocksare formed, one pair being associated with each of the guide rods 22,and one of the blocks of each pair being fixed relative to the rod andone being slideable relative to the rod, so that the blocks are slidablerelative to each other along a defined path.

Means are provided to draw the four comer blocks togethersimultaneously, such means'preferably comprising a flexible cord 24which passes about the periphery of the corner blocks, thus encirclingthe blocks. Each of the blocks l2, l4 and 16 has a short diagonalhorizontal passageway 26 drilled between its two exterior faces adjacentthe upper outer corner thereof, as best seen in FIGS. 1 and 6, thepassageway being of a suitable cross section to permit the cord 24 toslide loosely therethrough. The passageways 26 are preferably alllocated at the same height and approximately midway between the top ofeach block and its horizontal surface 20.

Corner block 10 has secured thereto means for tightening the cord 24 soas to simultaneously draw all the corner blocks together. The tighteningmeans preferably is in the form of a winding spool generally designated28, and as best seen in FIG. 5, the spool comprises a housing 30fastened by wood screws 31 or any other suitable securing means to theexterior of comer block 10, a winding shaft 32 rotatably journaledwithin housing 30 and upon which the cord 24 is wound. Shaft 32 hasthree axially spaced flanges 34 thereupon which divide the shaft intotwo separate winding sections for maintaining the ends of cord 24separate from each other. Shaft 32 extends through the wall of housing30 opposite comer block 10 and terminates in a hand operated turningmeans such as a winding cylinder 36 rigidly attached to the shaft. Afterthe cord 24 has been passed around each of the comer blocks 12, 14 and16 and threaded through the respective passageways 26 therein, the freeends of the cord are passed through passageways 38 in housing 30, whichextend into the interior of the housing, and are wound upon the twowinding sections of shaft 32. lt will be appreciate that if both ends ofthe cord 24 are wound upon the shaft 32 in the same direction, then byrotating the winding cylinder 36 and hence the shaft 32, both ends ofthe cord 24 will be drawn into the spool and will thereby simultaneouslydraw the four comer blocks together and maintain an object held thereinunder compression, the degree of which can be regulated by winding thecord 24 to any desired tension.

Cooperating means are provided between the housing 30 and the windingcylinder 36 to lock the cylinder 36 and hence winding spool 28 againstundesired rotation. As seen in FIGS. 3 and 4, the winding cylinder 36 isof such diameter as to extend somewhat above the top of housing 30.Drilled in the circular surface of the cylinder facing housing 30, andadjacent the periphery thereof, are a number of recesses or holes 40which are circumferentially spaced and extend into the cylinder a shortdistance sufficient to receive a locking pin 42. The pin 42, in itspreferred embodiment, is hooklike in configuration, and mayadvantageously comprise a conventional door hook. This hook preferablyis pivotably secured to the top surface of spool housing 30 about screw44 so as to pivot generally parallel to the top surface of the housing.It will be seen from FIG. 4 that as the winding cylinder 36 is rotatedto tighten the cord 24, pin 42 may be pivoted to enter any one of theholes 40 and thereby lock the cylinder 36 against additional rotation orunwinding thus maintaining the cord 24 at any desired degree of tension.Due to the hooklike configuration of member 42, the hook will tend toseat itself in the hole 40 under rotational tension of the cylinder 36and will thus resist accidental displacement from the hole.

As will be appreciate, when the clamp is empty and the cord 24 istightened, corner blocks l0, l2, l4 and 16 will be drawn together untilthey abut each other; further tightening of the cord will merelyincrease the tension on the cord. It is clear, therefore, that withoutfurther modification, the smallest dimension of a picture frame whichcan be held by the clamp is equal to the combined lengths of twoadjacent vertical wall sections 18, i.e., the minimum possible dimensionacross the interior recess between opposing walls 18. FIGS. 6 and 7 showmeans by which frames smaller than this minimum size may advantageouslybe clamped. An insert member 46 is provided for each of the cornerblocks, each insert preferably being L- shaped and having an outerlength and width substantially equal to the length of a vertical wall18, and a height approximately equal to the height of the vertical wall18. The inside vertical walls 48 of the L-shaped insert member 46 may beof any suitable length smaller than that of one of the walls 18, butshould provide sufficient area to support the sides of a frame in thesame manner as walls 18. it will be noted that inasmuch as the insetmembers 46, in effect move vertical walls 18 inwardly, a much smallerframe can be clamped through use of these insert members than throughthe use of the corner blocks alone.

Operation the clamp should be evident from the above description of itsstructure. Glue or cement or other securing means is first applied tothe four sides of a picture frame at their mitred ends. The sides arethen inserted into the open clamp, and winding cylinder 36 is thenrotated to draw the corner blocks 10, 12, 14 and 16 together. As this isdone, the blocks will adjust themselves to the particular proportions ofthe rectangular frame being assembled, by virtue of the fact that theblocks are individually free for movement along guide rods 22 in onedirection and the rods themselves are free to move closer together orapart in the other direction of a twodimensional system. When the clamphas contracted in size to the dimensions of the frame, the cylinder 36may be further rotated to place the cord 24 under any desired degree oftension and hence place any desired degree of compression on the frame.The locking hook member 42 is then pivoted to engage one of the holes 40in cylinder 36 to lock the cylinder against rotation and preventinadvertent loosening of the clamp. When it is desired to open theclamp, hook member 42 is pivoted out of the hole 40, and the tension onboth ends of cord 24 will tend to unwind cylinder 36, or it can beunwound by hand, thus relieving the compression forces on the cornerblocks and permitting removal of the finished frame.

it will be appreciated that by virtue of the novel describedconstruction, the inventive clamp is capable of use over a wide range ofsize adjustments. Without the provision of insert members 46, theminimum size frame that can be clamped is limited to the distance acrossthe interior recess of the closed clamp between vertical walls 18. Yet,still smaller frames can be clamped with the L-shaped insert members 46of the invention, and thus, essentially no lower limit need be imposedon the size of the frame that can be effectively clamped. At the otherextreme, the maximum size of frame that can be clamped is limited onlyby the length of cord available, and by the length of rods 22.

While all four corner blocks are free for movement relative to eachother, subject to the tightening or loosening of cord 24, blocks 10 and16 are maintained in proper aligned orientation relative to each other,by reason of the sliding fit upon rod 22, as are blocks 12 and 14. Inthe slackened state of the clamp, this alignment facilitates properinsertion of the components of a picture frame since the corner blocksof the clamp will tend to assume a rectangular configuration even withthe cord 24 slackened. When the clamp is tightened about a frame, theserods define a directional axis along which the blocks of each pair canbe displaced and thus aid in maintaining the blocks of each pair inproper alignment and effectively prevent the possibility of the clampfolding vertically upon itself as the result of too great tension on thecord 24.

It should now be apparent from the foregoing description of a preferredinventive embodiment that all the objects set forth at the outset ofthis specification have been successfully achieved.

What is claimed is:

l. A clamp for securing the sides of a rectangular frame or the like inassembled relationship comprising:

a plurality of four individual corner blocks, each block being recessedto grip one corner of a rectangular frame;

a plurality of elongate guide members extending in general parallelismwith each other from respective adjacent blocks to and slidably throughopposite respective adjacent blocks to constrain the blocks of eachopposite pair to movement toward and away from each other, said pairs ofopposite blocks being unconstrained relative to each other;

a flexible member extending about all of said plurality of blocks; and

means secured to one of said blocks to tighten the said flexible member,thereby displacing the blocks of each opposed pair along the directionof constraint and displacing said pairs of opposed blocks toward oneanother in a direction transverse to direction of constraint so as todraw all of said blocks together and clamp the rectangular frametherebetween.

2. A clamp as defined in claim 1, wherein said tightening meanscomprises a rotatable cylindrical spool and a fixed housing for saidspool disposed on one of said blocks, said flexible member being woundupon said spool, whereby rota tion of said spool causes said flexiblemember to be further wound thereupon to draw said blocks together.

3. A clamp as defined in claim 2, further comprising locking means tolock said rotatable spool against rotation.

4. A clamp as defined in claim 3, wherein said locking means comprises aseries of holes circumferentially spaced about the periphery of saidcylindrical spool and a hook member secured to said housing andselectively pivotable to engage one of said holes to lock said spoolagainst rotation.

5. A clamp as defined in claim 3, wherein said guide members compriserods, each of said rods being secured to one of removable insert meansfor each recessed portion for reducing the effective dimension of eachrecessed portion.

1. A clamp for securing the sides of a rectangular frame or the like inassembled relationship comprising: a plurality of four individual cornerblocks, each block being recessed to grip one corner of a rectangularframe; a plurality of elongate guide members extending in generalparallelism with each other from respective adjacent blocks to andslidably through opposite respective adjacent blocks to constrain theblocks of each opposite pair to movement toward and away from eachother, said pairs of opposite blocks being unconstrained relative toeach other; a flexible member extending about all of said plurality ofblocks; and means secured to one of said blocks to tighten the saidflexible member, thereby displacing the blocks of each opposed pairalong the direction of constraint and displacing said pairs of opposedblocks toward one another in a direction transverse to direction ofconstraint so as to draw all of said blocks together and clamp therectangular frame therebetween.
 2. A clamp as defined in claim 1,wherein said tightening means comprises a rotatable cylindrical spooland a fixed housing for said spool disposed on one of said blocks, saidflexible member being wound upon said spool, whereby rotation of saidspool causes said flexible member to be further wound thereupon to drawsaid blocks together.
 3. A clamp as defined in claim 2, furthercomprising locking means to lock said rotatable spool against rotation.4. A clamp as defined in claim 3, wherein said locking means comprises aseries of holes circumferentially spaced about the periphery of saidcylindrical spool and a hook member secured to said housing andselectively pivotable to engage one of said holes to lock said spoolagainst rotation.
 5. A clamp as defined in claim 3, wherein said guidemembers comprise rods, each of said rods being secured to one of theblocks of its respective pair with the other block of said pair slidablymounted thereupon.
 6. A clamp as defined in claim 1, in combination withremovable insert means for each recessed portion for reducing theeffective dimension of each recessed portion.